The chemical name of linezolid is (S)—N-((3-(3-fluoro-4-(-4-morpholinyl)phenyl)-2-oxo-5-oxazolidinyl)methyl)acetamide, and the structural formula is shown in the following figure:

Linezolid is a fluorine-containing oxazolidine antibacterial drug developed by Pharmacia & Upjohn CoMP1100611 any, and is marketed in the United States in 2000. This drug is novel in structure and unique in mechanism of action, and is used as an antibacterial drug for the treatment of infections by multi-drug resistant Gram positive bacteria and Bacillus tuberculosis, etc. This drug has attracted much attention in the field of medicine both at home and abroad, due to that it has no cross-resistance with other antibacterial drugs, and it is expected to become another major category of novel synthetic antibacterial drugs after sulfonamides and quinolones.
There are numerous synthetic methods, of which several relatively important ones are as follows:
A. prepared by acetylation of corresponding amine or ammonium salt (Moran R, et al., Org. Lett., 2008, 10(10), 1935-38):

B. prepared by condensation of key intermediate N-alkoxycarbonyl-3-fluoro-4-morpholinylaniline (B1) and chiral intermediate B2 (William R, et al., WO 02085849, 2002):

C. prepared by condensation of intermediate B1 and chiral starting material C2 to obtain the key intermediate C1, which is then transformed into the target product (refer to Brickner S. J., et al., J. Med. Chem, 1996, 39(3), 673-9):

D. prepared by cyclization of key intermediate D1 and triphosgene to obtain the product (refer to China Patent CN101220001A):

E. prepared by condensation of starting material isocyanate E2 and chiral starting material compound of formula E3 to obtain the key intermediate E1, which is then cyclized to prepare the product (B. A. Pearman: CN1275122A, 2000-11-29; B. A. Pearman: CN101353313A, 2009-01-28):

Each of the above routes has its advantages and disadvantages, and the common feature thereof is that the starting materials A1, B1, C1, D1 and E1 all contain 3-fluoro-4-morpholinylaniline group in their main structure, and as a mater of fact, 3-fluoro-4-morpholinylaniline (F1) is also the common starting material of the above-mentioned intermediates of A1, B1, C1, D1, E1, etc:

However, there is currently no report of synthesizing linezolid directly by using F1.